1. Field of the Invention
This invention relates generally to a latch for use on the door of an automobile and, more particularly, to a latch in which a latch element and a pawl are mounted for respective turning movement on a pair of pins secured in a base plate by swaging and are relatively positioned for engagement.
2. Description of the Prior Art
In a known latch for an automobile door, such as disclosed in the specification of U.S. Pat. No. 3,614,146, a pair of pins are set upright, at their one ends, in a base plate by swaging. A latch element is rotatably mounted on one of the pins and a pawl similarly on the other pin. A latch returning spring is connected to the latch element. The whole structure of the latch is then completed by attaching another separate base plate to the other ends of the pins by swaging.
In the structure of this type, both ends of either pin must be swaged to the respective separate base plate. Namely each pin has to be caulked at two portions, at its both ends, and it has been expected to reduce the number of swaging procedures.
In the factory where the inventor works, the following process is adopted. A base plate provided with at least two holes for swaging, a hollow recessed body member provided with at least two holes, a pair of pins each having a swaging stepped portion at its one end and a head portion with an enlarged diameter at its other end, a latch element, a latch returning spring and a pawl are prepared. When these component parts are assembled to an automobile door latch, the two pins, except their head portions, are first inserted through the two holes bored in the body. Then the latch element is mounted on one of the pins and the pawl on the other pin. A positional relationship is established in which the latch element and the pawl are engageable with each other and both rotatable. Further, the work to put the body on the base plate and the work to insert the free ends of both pins into the holes for swaging in the base plate are simultaneously carried out. The free ends of the pins are then secured in the base plate by swaging and the body is thus united with the base plate. In this manner, the base plate and the body form a casing enclosing the latch element and the pawl. This latch assembling process has the advantage that only one swaging work suffices for each pin by assembling the separately prepared component parts, the body, the latch element, the pawl, pins and the base plate, in the above mentioned manner.
When the free ends of the both pins are inserted into the holes in the base plate, the latch returning spring is, however, already attached to the latch element in advance. The spring exerts a force on the latch element in the direction perpendicular to the turning axis of the latch element. On account of this force, the latch element inclines one of the pins. It is difficult to insert the free ends of one inclined pin and the other upright one into the two holes in the base plate. It is impracticable and troublesome to put simultaneously the body over the base plate and to insert the pins into the holes.
On the other hand, the pins, and the latch element and pawl mounted both rotatably on them are, in general, made of metallic materials. Consequently an undesirable noisy metallic sound is uttered due to the direct contact and collision between metallic component parts every time the latch element is operated.